Which type of UV radiation primarily causes skin aging?

UVA radiation is primarily responsible for skin aging due to its ability to penetrate deep into the skin layers, reaching the dermis where collagen and elastin fibers are located. This damage leads to the breakdown of these essential proteins, resulting in the signs of aging such as wrinkles and loss of skin elasticity. UVA rays are present during all daylight hours and can penetrate through windows, making consistent protection necessary even when indoors or on cloudy days.

In contrast, UVB rays, while responsible for causing sunburn and contributing to skin cancer, primarily affect the outer layer of the skin and do not penetrate as deeply as UVA rays. UVC rays are mostly absorbed by the Earth’s atmosphere and do not typically reach the surface, making them less relevant in terms of day-to-day skin exposure. Infrared radiation is associated with heat and does not cause skin damage in the same way as UV radiation does; it involves different mechanisms which do not directly contribute to skin aging.